Protection arrangements are preferably used in connection with universal joint shafts that drive aggregates in agricultural implements. The universal joint shafts transmit torque from a main power train to an auxiliary drive or to individual aggregates. Universal joint shafts are also used to drive agricultural implements. The joint shaft is arranged between a tractor power take-off shaft and an implement drive input trunnion. Universal joint shafts comprise two universal joints and a connection shaft. The connection shaft connects the two universal joints. The connection shaft is telescopic along a longitudinal axis. The protection arrangement serves as a contact protection device for the universal shaft. The protection arrangement is accommodated in a supported manner on the universal shaft. The protection arrangement generally includes, for each universal joint, a protection cone and protection tube elements. The tube elements and cone are displaceable relative to each other along the longitudinal axis. One protection cone and a protection tube element are rotatably and axially non-displaceably retained by a bearing on one universal joint.
The protection device is retained, by being for example, connected via a chain to a fixing point of the implement. This is shown in DE 10 2010 000 900 A1. The universal joint shaft is rotatably supported, via bearings, in the protection arrangement. Thus, the protection device rotates with the shaft, especially in well known mountings, by slide bearings due to the drag torques. This is prevented by the use of the chain. In this case, the protection device can only rotate with the universal shaft until the chain is tensioned. Thus, further rotation of the protection device is prevented.
EP 0 908 083 B1 describes a protection arrangement of the above named type. In this case, one of the two protection cones, of the protection device, is fixingly connected at one axial end to a sleeve. This serves to stiffen the protection cone since the protection cone is formed as an elastic boot. The sleeve is connected, via screws, to a cone-like portion of the protection cone. The sleeve can be pushed axially outside onto the protection pot. The sleeve has circumferentially distributed inwardly projecting key projections to ensure a relatively non-rotating connection of the sleeve and thus of the protection cone and of the protection pot. Circumferentially distributed grooves, to engage the key projections, are correspondingly formed in the protection pot. The key projections and the grooves extend parallel to a longitudinal axis. Thus, the sleeve can be axially pushed onto the protection pot and carry out axial movements, relative to the protection pot, following articulation of the joint and deformation of the protection cone.
EP 0 173 898 B1 illustrated a protection device for a drive shaft of a front-wheel drive of an agricultural tractor. The protection device includes a protection tube that extends coaxially to the drive shaft and accommodates a cylindrical bearing sleeve that is supported on the shaft. The bearing sleeve is screwed onto a portion of the gearbox housing. The protection tube has at one end, facing the bearing sleeve, an open semi-circular alignment opening. The opening comes to rest in the area of a threaded bore of the bearing sleeve. A holding element, with a retaining disc, is screwed into the threaded bore to retain the protection tube axially and tangentially.